Those metal / plastic letters are fixed using simplefix stud fasteners, which are drilled through a paper or thin fabric drilling pattern. the pattern is the torn away and plasplugs are fitted into all the holes. Each letter has a sequence number written on the rear. I could imagine that the example shown could have happened if the fitter mis-counted the centre set of holes !
These ballz ups have occurred, especially as the pattern is rolled out bit by bit and you may be working from a single ladder.. I KNOW as I've been personally responsible for doing it !
This actual picture COULD well be a photoshop but I've seen much worse in my graphics supply experience !